Automatic cylinder tracking apparatus



Feb. 2, 1965 E. G. MASTROIANNI ,1

AUTOMATIC CYLINDER TRACKING APPARATUS Filed Feb. 18, 1963 2 Sheets-Sheet1 INVENTOR. EMILIO G. MASTROIANNI 21 AM A f) T. W Q$\\\H K ll -v\ WN 9%mm Wm illllllnfilll I|||||| uwulllllll N H m N\ N\ m NM NM. N

Feb. 2, 1965 E. s. MASTROIANNI 3,168,027

AUTOMATIC CYLINDER TRACKING APPARATUS Filed Feb. 18, 1963 2 Sheets-Sheet2 INVENTOR. EMILIO G. MAS OIANNI United States Patent 3,168,027AUTOMATIC cYLINDER TRACKING ArPARATUS This invention relates toimprovements in automatic cylinder tracking mechanisms, particularlyadaptable to the exposing or printing cylinder of a diazotype printingand developing apparatus.

Diazotype photocopying machines are widely employed in industry formaking exact duplicates of translucent originals, such as drawings orletters, delivering a positive copy which can be immediately usedwithout further processing or drying. For this reason, these machinesare generally termed dry printing and developing machines, todistinguish them from other types in which the exposed material isliquid developed and thereafter must be dried before it can be used.

Diazotype machines have generally three functional component assembliescombined into one operating unit. The first assembly, designated as aprinter, generally includes a transparent rotating cylinder enclosing asource of high-intensity mercury arc light. The sensitized material, incontact with the original, is fed around the surface of the cylinder tobe exposed to the high-intensity light. The second assembly is aseparator conveyor unit for separating the original from the sensitizedmaterial and conveying the sensitized material to a developer; and thethird assembly is a developer unit where the exposed, sensitizedmaterial is subjected to the vapors of a volatile developing agent, suchas aqueous ammonia, and thereafter delivered to a receiving tray.

In the printing unit to which this invention is directed, the rotatingcylinder is generally supported upon fixed rollers which function asbearings. In the larger machines, this construction has caused aconsiderable problem due to the fact that the cylinder will tend tocreep laterally as it is rotated. This lateral movement can causechipping of the edges of the cylinder or breakage thereof. Accordingly,it is a primary object of this invention to provide an improvedautomatic cylinder tracking mechanism, including a cylinder supportarrangement which senses any creep of the cylinder and corrects thetrack by displacement of the cylinder automatically in the oppositedirection, thus keeping the cylinder centered between its supportbearings.

A particular feature of this invention is that the cylinder supportrollers or bearings are carried by a pivotable caster arm which, inturn, is moved in response to a thrust bearing that senses axialdisplacement of the cylinder to cause tracking of the cylinder in theopposite direction.

Other objects and features will be apparent from the followingdescription of the invention, pointed out in particuiarity in theappended claims and taken in connection with the accompanying drawingsin which:

FIG. 1 is a side view illustrating the automatic cylinder trackingmechanism of this invention at both ends of the rotatable cylinder; and

PEG. 2 is a perspective view further illustrating the component parts ofone of the automatic tracking units.

During the exposing or printing operation, the sensitized material incontact with an original is fed around the periphery of a rotatingcylinder which contains a highintensity light source. As mentionedbefore, during rotation, the cylinder tends to creep laterally orhorizontally. If means are not present to prevent this creep, the edgesof the cylinder are likely to chip and break and other 3,168,027Patented Feb. 2, 1965 disadvantages ensue. This invention provides aunique mounting arrangement for supporting the printing cylinder on apair of roller supports or bearings which are mounted on a pivotablecaster arm and this arm, in turn, is controlled in its pivotal movementby an end thrust bearing which senses any lateral creep of the cylinderand positions the support rollers or bearings so as to track thecylinder in the opposite direction. There are two such automatictracking units, one at each end of the cylinder and they areappropriately interconnected so that the cylinder is always effectivelycentered.

Referring now to the drawings, the cylinder 10 is constructed of glassand usually contains a high-intensity light source therein (not shown).An original and sensitized sheet are fed in contact with each other bymeans of belts 12 around a portion of the cylinder 10. The friction ofthe moving belts 12 also rotates the cylinder 10.

At each end of the cylinder 10, there is an automatic tracking unit 14and 14. Since each of these units and each of the components therein areidentical at each end of the cylinder, only one of the units will bedescribed in detail and the corresponding unit at the opposite end ofthe cylinder will be designated by the identical reference numeralsbearing primary indices.

The tracking mechanism 14 is mounted on a support which may be a castinghaving a flange 20 and a cylindrical collar portion 22. It is attachedto end plate 16. A stepped cutout 24 is provided in the collar portion22 and an integrally cast yoke support 26 is provided at the bottom ofthe collar portion 22.

The yoke support 26 rotatably carries a bifurcated caster arm 28 forpivotal movement about the axis 30. The cylinder 10 has a collar 32 atthe end thereof which is supported by a pair of rollers 34 and 35,rotatably mounted on stub shafts 36 which, in turn, are carried by theends 38 of the caster arm 28.

An end thrust roller 40 is positioned to contact the edge of the collar32 and is, therefore, mounted in a plane substantially perpendicular tothe mounting of the support roller 34. The end thrust roller 40 isrotatably mounted on a shaft in the arm 42 rigidly secured to the casterarm 28 by a securing nut 44.

A bracket 46 is secured to the end 38 of the caster arm 28 and isconnected to a tension spring 50 which, in turn, is connected to a cable51. The cable 51 interconnects the two automatic tracking units forsubstantially simultaneous movement.

The operation of the invention will now be described. The cylinder 10,having end collars 32 and 32', is rotated by means of the belts 12. Thecollars 32 and 32 rest upon rollers 34, 34 and 35, These rollers, inturn, are mounted on caster arms 28 and 28 so that they can be displacedfor the purpose of cylinder tracking.

As the cylinder 10 is rotating, it has a tendency to creep laterally.The arrangement of this invention keeps the cylinder within a confinedarea and opposes the tendency toward lateral creep. The thrust bearingsand 40' contact the ends of the cylinder 10 and any lateral movement ofthe cylinder causes the thrust bearings 40 and 40' to pivot the casterarms 28. Pivotal movement of caster arms 28 moves the rollers 34 and 35so as to counteract the lateral shift of the cylinder 10. For example,if the cylinder 10 tends to creep toward the right, then the rollers 34and 35 would be displaced by a slight turning of the arm 28 around thepivotal axis 30. Due to the interconnection of units 14 and 14' by meansof the cable 51, the rollers 34 and 35' will partake in similarcompatible movement causing a shift of the cylinder in the samedirection. In a similar manner, but in an opposite sense, if thecylinder 10 tends to creep toward the left, the opposite result will beobtained.

Although the automatic tracking arrangement of this invention utilizinga caster effect and a sensing end thrust roller is especially applicableto printing cylinders of diazotype printing machines, it will beapparent to those skilled in the art that other rotatable cylinderscould be similarly tracked automatically.

What is claimed is:

1. An automatic cylinder tracking apparatus which comprises:

(a) bearing means for rotatably supporting the cylinder,

(b) caster arms carrying the rotatable support bearing means,

(0) a stationary support means for pivotally supporting the caster arms,and

(d) an end thrust sensing means connected to the caster arms and adaptedto contact the cylinder and sense lateral displacement thereof, so thatany lateral creep of-the rotating. cylinder which is sensed by the endthrust sensing means, will be transmitted to the caster arm which, inturn, positions the rotatable support bearings for tracking the cylinderin a direction opposite to the direction of lateral creep.

2. An apparatus for keeping a rotating cylinder substantially centeredwithin'rotatable bearing rollers sup- "s porting means to the casterarms, the caster arms being pivotable to move the rotatable bearingrollers and to thereby track the cylinder in a direction opposite to thedirection of lateral movement.

3. An apparatus as defined in claim 2 further comprising resilient meansconnecting each of the bifurcated caster arms for substantiallysimultaneous movement.

4. In combination with-a printing and exposing unit of a diazotype copymachine including a glass printing cylinder with end collars, beltscontacting the periphery of the cylinder for rotating the same, animproved cylinder tracking apparatus comprising:

(a) a stationary support adjacent each end of t e rotatable cylinder andat least partially enclosing the end collars thereof,

(b) a bifurcated caster arm pivotally mounted by the stationary support,there being a caster arm for each end of the cylinder,

(0) rotatable bearing rollers for contacting the collars of the glasscylinder and rotatably supporting the cylinder,

(d) means mounting the bearing rollers to each end of each of thebifurcated caster arms,

(2) a pair of end thrust rollers, each adapted to contact an oppositeend of the cylinder,

(f) means for supportingthe end thrust rollers from the caster arm suchthat movement of the cylinder against the end thrust rollers causescorresponding movement of the caster arm, and

(g) resilient means including a cable and tension springsinterconnectingthe bifurcated caster arms for substantially simultaneousmovement so that any sensed lateral creep of the cylinder will result inrepositioning the pivotable caster arms and rotatable supports carriedthereby to cause the cylinder to track in a direction opposite to thecreep.

No references cited.

4. IN COMBINATION WITH A PRINTING AND EXPOSING UNIT OF A DIAZOTYPE COPYMACHINE INCLUDING A GLASS PRINTING CYLINDER WITH END COLLARS, BELTSCONTACTING THE PERIPHERY OF THE CYLINDER FOR ROTATING THE SAME, ANIMPROVED CYLINDER TRACKING APPARATUS COMPRISING: (A) A STATIONARYSUPPORT ADJACENT EACH END OF THE ROTATABLE CYLINDER AND AT LEASTPARTIALLY ENCLOSING THE END COLLARS THEREOF, (B) A BIFURCATED CASTER ARMPIVOTALLY MOUNTED BY THE STATIONARY SUPPORT, THERE BEING A CASTER ARMFOR EACH END OF THE CYLINDER, (C) ROTATABLE BEARING ROLLERS FORCONTACTING THE COLLARS OF THE GLASS CYLINDER AND ROTATABLY SUPPORTINGTHE CYLINDER, (D) MEANS MOUNTING THE BEARING ROLLERS TO EACH END OF EACHOF THE BIFURCATED CASTER ARMS, (E) A PAIR OF END THRUST ROLLERS, EACHADAPTED TO CONTACT AN OPPOSITE END OF THE CYLINDER,